This invention relates to the field of brachytherapy and the manufacture and handling of small radioactive seeds. Brachytherapy involves the implantation of small radioactive seed, or pellets into tumors to eradicate cancerous cells, and is an alternative to external radiation therapy such as electron beam irradiation.
Brachytherapy has been used in the treatment of numerous types of cancer, including cervical, breast, lung, head and neck, and prostate. As an example of the procedure the treatment of prostate cancer will be used. This is in no way intended to limit the scope of this application, as the use of the invention disclosed herein has general application in the handling of the radioactive pellets, or seeds, as will be obvious to those skilled in the art.
The treatment of prostate cancer using radioactive seed implantation has been known for some time. Currently either Palladium-103 or Iodine-125 seeds are used, with apparent activities ranging from about 0.25 mcuries to 1.2 mcuries, depending on the prostate size and aggressiveness of the cancer. Recent advances in ultrasound imaging and other technological advancements have enabled this procedure to become a very viable alternative to other treatments such as external beam irradiation and radical prostatectomy. The procedure involves ultrasound mapping of the prostate gland and size of tumor using a transrectal ultrasound probe. A radiation oncologist will then decide on the number and positioning of the radioactive seeds needed to deliver a sufficient amount of radiation to kill the cancerous cells. The requisite number of radioactive seeds are typically loaded into 18 gauge brachytherapy needles. Needles may contain anywhere from one to seven seeds, usually separated by bio-absorbable spacers of catgut or other suitable suture material. To prevent the seeds and/or the spacers from falling out of the needle accidentally, the distal end of the needle, the tip, is plugged with a small amount of bone-wax. Bone-wax is a medical grade beeswax material. The seeds are prevented from falling out of the proximal or hub end of the needle by a blunt obturator, which is ultimately used to force the seeds from the 18 gauge needle once in position in the prostate. The needles are inserted into the prostate transperineally.
In a typical procedure the needles loaded with seeds are inserted into the prostate gland under the guidance of the ultrasound rectal probe. A metal grid, abutting the s peritoneum, having X-Y coordinates is matched to a grid overlaid on the real-time ultrasound picture, so that the requisite number of seeds can be placed at each location in accordance with the mapping planes used by the radiation oncologist to optimize dose delivery. Once the tip of the needle is visualized in the correct location on the ultrasound screen, the needle is withdrawn over the obturator whilst maintaining the position of the obturator, such that a pattern of seeds and spacers is laid down as required. Typically about 85 seeds are placed during the procedure, but the number can be as high as about 140 or as low as about 40. Thus a typical procedure uses about 30 needles per patient.
Currently the seeds and the spacers are loaded into the needles by the radiation oncologist or radiation physicist by hand. This is a laborious task, and can take up to an hour to complete. This can tie-up Operating Room time, and at a minimum is wasting radiation oncologist or physicist time. Furthermore, during this time the person doing the loading is exposed to undesirable levels of radiation, and the loading task is extremely fatiguing. Some mechanical assist devices exist, but they are either unreliable, and can jam or, even worse, break or crush a seed allowing radioactive material to escape. In addition, verification of seed loading per needle is generally not readily accomplished. A system marketed by Northwest Radiation Therapy Products organizes the seeds, spacers, and needles on a stand. This lessens operator movement, but the process is still time consuming.
An alternate approach for delivering the seeds to the patient is typified by instruments called the Mick Applicator and the Quick Seeder Applicator sold by Mick Radio-Nuclear Instruments, Inc. In this system the empty needles are first inserted into the patient at the predetermined locations. Then using the Mick Applicator one seed at a time is delivered from a pre-loaded cartridge, indexing back a pre-determined distance after delivering each individual seed. In the case of the Quick Seeder Applicator, a cartridge pre-loaded with seeds and spacers is attached to the needle. This device transfers a column of seeds and spacers by indexing back a pre-determined distance to accomplish the delivery. Again the cartridges are loaded either by hand or by using a device that consists of a chamber in which the seeds and spacers are lined up before being pushed into the cartridge. This is time consuming because seeds and spacers still have to be hand loaded into the transfer chamber, thus offering little benefit over straight hand loading. The invention described herein overcomes the deficiencies in the prior art and provides an improved means for loading needles. No supplier provides pre-loaded needles for brachytherapy.
U.S. Pat. No. 5,928,130 by Schmidt describes a tool for implanting radioactive seeds that includes a needle, spacers and seeds loaded into a transparent or translucent sleeve, and an obturator to facilitate the displacement of spacers and seeds and deposit them into tissue.
Notwithstanding the various efforts in the prior art, there remains a need for a preloaded brachytherapy seed system as described in detail below.
One aspect of the present invention is to enable brachytherapy needles to be preloaded with radioactive seeds and spacers, organized, packaged and shipped sterile in quantities prescribed on a per order basis. Another aspect of the invention is to provide one prescription in one shipper. Another aspect of the invention is to provide a system that allows for at least about 10% of the seeds to be assayed for activity without affecting the sterility of the pre-loaded seeds for implantation. Yet another aspect of the invention is to provide a system that allows for the addition of about two extra needles for insertion of extra seeds in order to accommodate unforeseen adjustments in the procedure.
Another aspect of the invention is to eliminate the preparation time at the clinical site of loading and sterilizing the seeds as required in the past. Yet another aspect is to reduce operator exposure to radiation to a minimum and to reduce Operating Room use, thus reducing costs. Another aspect of the present invention is to reduce the amount of paper work required by the hospital by reducing the invoicing, ordering and stocking from four individual products to one.
Another aspect of the invention is to provide a system that optimizes the needle layout by arranging the needles in order by needle number previously prescribed in the treatment plan. Yet another aspect of the invention is to provide a system that allows the user to remove any one of the needles at any time during the procedure and does not require that the needles be unloaded sequentially thus providing the physician with flexibility during the procedure without adding concern about potentially damaging the pre-loaded needles. Another aspect of the invention is to provide pre-loaded sleeves having a marker corresponding to the number of seeds in the sleeve. Another aspect of the invention is to provide pre-loaded sleeves identified with their corresponding needle numbers according to the pre-planned prescription information.
Another aspect of the invention is to provide a system that allows the loading pattern of each needle to be confirmed at any time up to and including the time of implant. The loading pattern is confirmed by removing the sleeve from the needle and viewing the seeds and spacers through the sleeve.
Yet another aspect of the invention is to provide a sterile system that eliminates the time and processing equipment needed to sterilize the components on site, thus reducing the cost. Another aspect of the invention is to provide a system that allows for double aseptic transfer of the injected components into the sterile field of the operating room.
Another aspect of the invention is to provide a system that allows the physician to implant seeds and spacers using their current method. Yet another aspect of the invention is to provide the physician with a tactile feedback of the dispensing of spacers and seeds, thus providing the user with a confirmation that spacers and seeds are being implanted.
The invention comprises a system of components that enable brachytherapy needles to be pre-loaded with radioactive seeds and spacers, organized, packaged and shipped sterile from the manufacturing facility to the clinical site in quantities prescribed on a per patient per order basis. In a preferred embodiment the seeds required for assay of the activity of the shipment are provided in a manner that does not compromise the sterility of the seeds for implantation. In a preferred embodiment additional extra empty needles are provided to accommodate unforeseen adjustments in the procedure that require insertion of extra seeds.
In a preferred embodiment, the seeds and spacers are loaded in transparent or translucent sleeves that allow visual confirmation of the loading pattern of seeds and spacers up to and including the time of implant. In a preferred embodiment the seeds and spacers are retained in the sleeve by a retaining element. In a preferred embodiment the system provides the physician with confirmation in the form of tactile feedback of the dispensing of each seed and each spacer.
In a preferred embodiment, the pre-loaded sleeves are marked with an indication of the number of seeds inside. In a preferred embodiment the pre-loaded sleeve is marked with an identifier indicating which corresponding needle it should be used with according to the pre-planned prescription information and treatment plan.
In a preferred embodiment the system allows for double aseptic transfer of the injected components into the sterile field of the operation room.
Thus, there is provided in accordance with one aspect of the present invention a brachytherapy seed and spacer deployment system, which includes a deployment device. The deployment device comprises an elongate tubular sleeve, having a proximal end and a distal end. An elongate obturator is axially movable through the tubular sleeve. At least one retention structure is provided on the tubular sleeve, for retaining brachytherapy seeds and spacers therein. The retention structure is movable between a first position in which it will retain a seed and spacer within the sleeve, and a second position in which it will release the seed and spacer separately from the sleeve.
Preferably, the retention structure is biased in the direction of the first position. The sleeve is also preferably visually transparent.
In one embodiment, the system further comprises a lock on the obturator, for resisting distal advancement of the obturator through the sleeve. The obturator lock may comprise a tubular wall, having an axially extending slot therein. The tubular wall surrounds a proximal portion of the obturator, which extends proximally from the tubular sleeve and prevents distal advancement of the obturator into the sleeve.
In accordance with another aspect of the present invention, there is provided a method of controllably deploying a plurality of seeds and spacers from a brachytherapy seed deployment device. The method comprises the steps of providing a brachytherapy seed deployment device, having a tubular body, a plurality of seeds and spacers therein, a deployment control, and a releasable retainer for preventing inadvertent release of seeds and spacers from the device. The device is positioned at a treatment site, and the control is manipulated to deploy a first seed past the retainer and from the device. The retainer is permitted to retain at least a spacer within the device. In one embodiment, the manipulating the control step comprises distally advancing an obturator. Preferably, the method further comprises the step of deploying at least a spacer past the retainer and from the device. In many applications, at least a second and often at least a third seed are controllably sequentially deployed.
In accordance with a further aspect of the present invention, there is provided a brachytherapy system. The system comprises an elongate tubular needle, and an elongate tubular sleeve positioned within the needle. The sleeve has a proximal end and a distal end. At least one brachytherapy seed is positioned in the sleeve, and an obturator extends into the proximal end of the sleeve. The needle is carried by a flexible drape. Preferably, a plurality of brachytherapy seeds and spacers are positioned within the sleeve. In addition, a plurality of needles are preferably carried by the drape.
The foregoing drape carrying a plurality of needles may be positioned within a needle pig. The system preferably additionally comprises one or more calibration seeds. The calibration seeds are preferably carried by a calibration seed pig, or carried in a calibration seed cavity on the needle pig, such that the calibration seeds can be accessed without exposing the needles.
In accordance with another aspect of the present invention, there is a provided a brachytherapy system. The brachytherapy system comprises a shipping container, having a needle pig carried therein. A calibration seed pig is also provided in the shipping container. A plurality of brachytherapy needles are positioned in the needle pig, the brachytherapy needles preloaded with brachytherapy seeds and spacers. At least one, and in some embodiments a plurality of calibration seeds are provided in the calibration pig, such that the calibration seed or seeds can be accessed without opening the needle pig.
Preferably, the brachytherapy needles are carried by a flexible drape. The system preferably additionally comprises a needle loading report, for identifying the contents of each needle and the target position for each needle in the patient.
In accordance with another aspect of the present invention, there is provided a nonuniform dosing profile brachytherapy needle set. The needle set comprises a flexible drape, and a plurality of needles, each containing at least one brachytherapy seed, the needles carried by the drape. At least a first seed in a first needle is provided with a first activity, and at least a second seed in a second is provided with a second, different activity. In one embodiment, at least a third seed having a third activity is positioned in the first needle.
In accordance with another aspect of the present invention, there is provided a nonuniform dosing profile brachytherapy seed deployment device. The device comprises a brachytherapy needle, and a tubular sleeve within the needle. A plurality of brachytherapy seeds and spacers are positioned within the sleeve, such that the device exhibits a first activity in a first zone and a second activity in a second zone.
In accordance with further aspects of the present invention, there are provided methods for customizing a dosing profile to the three-dimensional target tissue within a patient. The method comprises the steps of identifying the three-dimensional shape of the target tissue within a patient, and preloading a plurality of brachytherapy seeds having two or more activities into a plurality of brachytherapy needles in a pattern which corresponds to the three-dimensional profile of the target tissue. The brachytherapy needles are labeled and delivered to the clinical site. Each needle is thereafter inserted into its predetermined location within the target tissue, to reconstruct the predetermined three-dimensional dosing profile for that patient.
Further features and advantages of the present invention will become apparent to those of skill in the art in view of the detailed description of preferred embodiments which follows, when considered together with the attached drawings and claims.